Motor

ABSTRACT

A motor includes a rotor including a shaft centered on a vertically extending center axis, a stator radially opposite to the rotor and including coils, a bearing supporting the shaft, and a bus bar unit on an upper side in an axial direction of the stator. The bus bar unit includes bus bars including a terminal portion connected to a lead wire drawn out from the coil and a bus bar holder holding the bus bars. The terminal portion includes a slit which extends axially downward and into which the lead wire is fitted. The width of the slit is narrower than the diameter of the lead wire.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a motor.

2. Description of the Related Art

Japanese Laid-Open Patent Publication No. 2005-130586 discloses astructure of a wire connection process in a stator of an electric motor.The stator includes a stator core having a plurality of magnetic poleteeth along an inner circumferential portion and a winding wounddirectly around each magnetic pole tooth of the stator core via aninsulating member. At one end surface of the stator core, a cavityintegrally molded with the insulating member and serving as a wirereceiving portion is disposed. An insulation displacement terminalhaving a conduction groove is inserted in the cavity, and the windingand the crossover wire or the lead wire are electrically connected.Specifically, since the winding and the insulation displacement terminalare conducted and the lead-side crossover wire and the insulationdisplacement terminal are conducted, the winding and the lead-sidecrossover wire are connected. Likewise, the winding and the neutralpoint-side crossover wire are in a connected state by the insulationdisplacement terminal.

In the connection processing structure disclosed in Japanese Laid-OpenPatent Publication No. 2005-130586, it is necessary that the insulationdisplacement terminals are separately inserted for each cavity so as toconnect the winding with the lead-side crossover wire or the neutralpoint-side crossover wire. For this reason, there is a concern that theman-hours required for manufacturing the electric motor may beincreased.

SUMMARY OF THE INVENTION

A motor according to an exemplary embodiment of the present inventionincludes a rotor including a shaft centered on a vertically extendingcenter axis, a stator disposed radially opposite to the rotor andincluding a plurality of coils, a bearing supporting the shaft, and abus bar unit disposed on an upper side in the axial direction of thestator. The bus bar unit includes a plurality of bus bars including aterminal portion connected to a lead wire drawn out from the coil and abus bar holder holding the plurality of bus bars. The terminal portionincludes a slit which extends axially downward and into which the leadwire is fitted. The width of the slit is narrower than the diameter ofthe lead wire.

An exemplary embodiment of the present invention provides a techniquecapable of improving manufacturing efficiency of a motor including a busbar.

The above and other elements, features, steps, characteristics andadvantages of the present invention will become more apparent from thefollowing detailed description of the preferred embodiments withreference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view of a motor according to anexemplary embodiment of the present invention.

FIG. 2 is a vertical sectional view of a motor according to an exemplaryembodiment of the present invention.

FIG. 3 is a perspective view of the motor shown in FIG. 1 with the rotorand the bus bar unit removed.

FIG. 4 is a schematic perspective view of a core back included in astator core according to an exemplary embodiment of the presentinvention.

FIG. 5 is a schematic perspective view of a tooth portion included in astator core according to an exemplary embodiment of the presentinvention.

FIG. 6 is a schematic diagram for explaining a step (c).

FIG. 7 is a schematic diagram for explaining a step (d).

FIG. 8 is a perspective view of a bus bar unit included in a motoraccording to an exemplary embodiment of the present invention.

FIG. 9 is a plan view of a terminal portion provided at one end portionof a bus bar.

FIG. 10 is a vertical sectional view of a portion of an intermediatemember included in a motor according to an exemplary embodiment of thepresent invention.

FIG. 11 is a view for explaining the relationship between theintermediate member and the stator.

FIG. 12 is an enlarged view of a lead wire holding portion and itssurroundings.

FIG. 13 is a further enlarged perspective view of the lead wire holdingportion and its surroundings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, exemplary embodiments of the present invention will bedescribed in detail with reference to the drawings.

In the present description, the direction parallel to a center axis A ofa motor 1 is referred to as the “axial direction”, the directionperpendicular to the center axis A of the motor 1 is referred to as the“radial direction”, and the direction along a circular arc with thecenter axis A of the motor 1 as the center thereof is referred to as the“circumferential direction”.

In the present description, the axial direction when the motor 1 isdisposed in the direction shown in FIG. 2 is defined as the verticaldirection. The vertical direction is merely a name used for explanationand does not limit the actual positional relationship and direction.

<1. Schematic Configuration of Motor>

FIG. 1 is a schematic perspective view of the motor 1 according to anembodiment of the present invention. FIG. 2 is a vertical sectional viewof the motor 1 according to an embodiment of the present invention. Asshown in FIG. 1 and FIG. 2, the motor 1 has a rotor 10, a stator 20, abearing 30, a bus bar unit 40, a housing 50, and an intermediate member60.

As shown in FIG. 2, the rotor 10 has a shaft 11 centered on the centeraxis A extending in the vertical direction. The shaft 11 is circular inplan view from the axial direction. The shaft 11 may be columnar ortubular. The shaft 11 is made of a metal. In addition to the shaft 11,the rotor 10 includes a rotor core 12 and a magnet 13.

The rotor core 12 is cylindrical. The rotor core 12 is disposed radiallyoutside of the shaft 11. The rotor core 12 has a configuration in whicha plurality of magnetic steel plates are laminated in the axialdirection. However, the rotor core 12 may be, for example, a sinteredbody obtained by sintering a magnetic material or the like. The shaft 11is, for example, fixed to the rotor core 12 by press-fitting into thecenter portion of the rotor core 12. A plurality of magnets 13 aredisposed radially outside of the rotor core 12. The plurality of magnets13 are arranged in the circumferential direction. The magnet 13 is apermanent magnet for a field, and may be, for example, a sinteredmagnet, a bonded magnet, or the like.

FIG. 3 is a perspective view of the motor 1 shown in FIG. 1 with therotor 10 and the bus bar unit 40 removed. With reference to FIG. 2 andFIG. 3, the stator 20 will be described. The stator 20 is disposed toface the rotor 10 in the radial direction. In the present embodiment,the stator 20 is provided in a substantially annular shape and isdisposed radially outside of the rotor 10. However, the stator 20 may bedisposed radially inside of the rotor 10. In this case, the rotor needsto be changed from the configuration of the present embodiment, and itis configured, for example, in a cup shape. The stator 20 is an armatureof the motor 1. The stator 20 includes a stator core 21, a plurality ofcoils 22, and an insulator 23.

The stator core 21 is annular. The stator core 21 includes a pluralityof teeth 211 arranged in the circumferential direction and an annularcore back 212. In other words, the stator 20 has the plurality of teeth211 arranged in the circumferential direction and the annular core back212. A conductive wire 221 constituting the coil 22 is wound around eachof the teeth 211. In detail, the conductive wire 221 is wound aroundeach of the teeth 211 via the insulator 23. The core back 212 ispositioned radially outside of the plurality of teeth 211.

The insulator 23 is disposed between the coil 22 and the teeth 211around which the conductive wire 221 constituting the coil 22 is wound.The insulator 23 is an insulating member that electrically insulates thestator core 21 and the coil 22. By supplying the drive current to thecoil 22, a magnetic flux in the radial direction is generated in theteeth 211 which are magnetic cores. As a result, a circumferentialtorque is generated in the rotor 10, and the rotor 10 rotates around thecenter axis A.

Here, a method of manufacturing the stator 20 will be described. FIG. 4is a schematic perspective view of the core back 212 included in thestator core 21 according to an embodiment of the present invention. FIG.5 is a schematic perspective view of a tooth portion 211P included inthe stator core 21 according to an embodiment of the present invention.As shown in FIG. 4 and FIG. 5, the stator core 21 has the core back 212and the tooth portion 211P which are members separated from each other.The stator core 21 is configured by combining the core back 212 and thetooth portion 211P. In the present embodiment, the core back 212 has aplurality of core back recesses 212 a recessed radially outward on theinner circumferential surface. Each of the core back recesses 212 aextends from the upper surface to the lower surface of the core back212. The plurality of core back recesses 212 a are arranged in thecircumferential direction. The number of the core back recesses 212 a isthe same as the number of the teeth 211 included in the tooth portion211P. The core back 212 and the tooth portion 211P are combined byfitting the distal end portion of radially outside of each of the teeth211 of the tooth portion 211P into the core back recess 212 a.

The method of manufacturing the stator 20 includes a step (a) ofpreparing the core back 212. For example, the core back 212 is formed bylaminating a plurality of annular magnetic steel plates. As anotherexample, the core back 212 may be formed by sintering a magneticmaterial.

The method of manufacturing the stator 20 includes a step (b) ofpreparing the tooth portion 211P. The tooth portion 211P has theplurality of teeth 211 arranged in the circumferential direction. Thetooth portion 211P has an annular coupling portion 211Pa that connectsthe radially inner end portions of the teeth 211 that are adjacent inthe circumferential direction. For example, the tooth portion 211P isformed by laminating a plurality of magnetic steel plates. As anotherexample, the tooth portion 211P may be formed by sintering a magneticmaterial.

The method of manufacturing the stator 20 has a step (c) of winding theconductive wire 221 around the insulator 23 in order to form the coil22. FIG. 6 is a schematic diagram for explaining the step (c). The step(c) is carried out, for example, using a nozzle winding machine. Asshown in FIG. 6, when the conductive wire 221 is wound around theinsulator 23, the plurality of insulators 23 are linearly disposed. As aresult, it becomes easy to wind the conductive wire 221 around each ofthe insulators 23, and it is possible to easily form the plurality ofcoils 22. Further, in the present embodiment, the coil 22 has threetypes of coils, a U-phase coil, a V-phase coil, and a W-phase coil. Thenumber of the coils 22 of each phase is the same and is plural. As anexample, the number of the coils 22 of each phase is four. The step ofwinding the conductive wire 221 around the insulator 23 to form the coil22 is carried out separately for each phase. That is, three sets of coilgroups integrated with the insulator 23 are prepared.

The steps (a), (b), and (c) may be carried out in order, but they may becarried out in parallel at the same time. If the steps (a), (b), and (c)are carried out in order, the order is not particularly limited and maybe started from any step.

The method of manufacturing the stator 20 includes a step (d) ofattaching the insulator 23 with the conductive wire 221 wound thereon tothe tooth portion 211P. FIG. 7 is a schematic diagram for explaining thestep (d). In the present embodiment, as described above, the three setsof coil groups integrated with the insulator 23 are prepared. Thesethree sets are sequentially attached to the tooth portion 211P. In thepresent embodiment, the U-phase coil, the V-phase coil, and the W-phasecoil are attached to the tooth portion 211P of the insulator 23 so as tobe repeatedly arranged in the circumferential direction in this order.More specifically, in each set, the insulator 23 is attached to everythree teeth 211 arranged in the circumferential direction. When beingattached, each of the tubular insulators 23 is inserted into each of theteeth 211 from radially outside.

The method of forming the coil 22 described above is merely an example.For example, after the insulator 23 is attached to the tooth portion211P first, the coil 22 may be formed by winding the conductive wire 221around the insulator 23. Although the insulator 23 is divided into aplurality of insulators 23 in the present embodiment, the number of theinsulators 23 may be integrated into one or a plurality of insulatorsless than the number of them in the embodiment.

The method of manufacturing the stator 20 includes a step (e) ofcombining the tooth portion 211P with the conductive wire 221 woundthereon and the core back 212. In the present embodiment, the core back211 is disposed in a position surrounding the tooth portion 211P. Thatis, the core back 211 is disposed radially outside of the tooth portion211P. A part of the inner circumferential surface of the core back 211is fixed in contact with the tooth portion 211P. The fixing method maybe, for example, press fitting, adhesion, or the like.

As shown in FIG. 2, the bearing 30 supports the shaft 11. The bearing 30is disposed radially outside of the shaft 11. Specifically, the motor 1has an upper bearing 30 a and a lower bearing 30 b, which are disposedat intervals in the axial direction. The upper bearing 30 a is locatedabove the rotor core 12. The lower bearing 30 b is located below therotor core 12. The shaft 11 is rotatably supported by these two bearings30 a and 30 b. In the present embodiment, the two bearings 30 a and 30 bare ball bearings. However, the number and type of bearings may bechanged. The bearing may be, for example, a sliding bearing or the like.

As shown in FIG. 2, the bus bar unit 40 is disposed axially above thestator 20. The bus bar unit 40 has a power supply structure thatsupplies power from the outside of the motor 1 to the plurality of coils22. As shown in FIG. 1 and FIG. 2, the bus bar unit 40 includes a busbar 41 and a bus bar holder 42. The bus bar unit 40 has the plurality ofbus bars 41 as described later. The bus bar holder 42 holds theplurality of bus bars 41. In the present embodiment, the bus bar unit 40holds the upper bearing 30 a. Details of the bus bar unit 40 will bedescribed later.

The housing 50 surrounds and fixes the stator 20. As shown in FIG. 3,the housing 50 is a bottomed cylindrical member having a housing opening50 a on the axially upper side. In the present embodiment, the housing50 is made of a metal. However, the housing 50 may be made of a materialother than a metal such as a resin. As shown in FIG. 2 and FIG. 3, thehousing 50 accommodates the rotor 10 and the stator 20.

As shown in FIG. 2, a cylindrical portion 51 having a diameter smallerthan that of the housing opening 50 a is provided in the center portionof the lower surface of the housing 50. The internal space of thehousing 50 and the internal space of the cylindrical portion 51 arecommunicated. The lower bearing 30 b is held by the cylindrical portion51. As shown in FIG. 1 to FIG. 3, the housing 50 has a flange 52 thatextends towards radially outside. In particular, the flange 52 isprovided on the upper end of the housing 50. The flange 52 is a memberidentical to the housing 50. For example, the flange 52 is formed bybending the upper end of the housing 50.

As shown in FIG. 2 and FIG. 3, the intermediate member 60 is locatedbetween the stator 20 and the bus bar holder 42. As shown in FIG. 3, theintermediate member 60 has a lead wire holding portion 61 that holds alead wire 222. According to the present configuration, workability canbe improved because it is possible to connect the bus bar 41 and thelead wire 222 with the lead wire 222 fixed by the lead wire holdingportion 61.

Note that the insulator 23 may be configured to have a lead wire holdingportion that holds the lead wire 222. In this case, it is preferablethat the lead wire holding portion is disposed on the upper portion ofthe insulator 23. Also in this case, workability can be improved becauseit is possible to connect the bus bar 41 and the lead wire 222 with thelead wire 222 fixed by the lead wire holding portion.

However, in the present embodiment, it is preferable that the lead wireholding portion is provided in the intermediate member 60. As describedabove, in the present embodiment, the stator core 21 is configured bycombining the two members of the tooth portion 211P and the core back212. In the case where the lead wire holding portion is provided in theinsulator 23, when the tooth portion 211P to which the insulator 23 isattached and the core back 212 are combined, the lead wire holdingportion is likely to hinder and make it difficult to insert the toothportion 211P into the core back 212. By disposing the lead wire holdingportion radially inside of the insulator 23, it is possible to avoid acontact between the lead wire holding portion and the core back 212.However, in this case, the lead wire holding portion is likely to hinderand make it difficult to wind the conductive wire 221 for constitutingthe coil 22 around the insulator 23. By having a configuration in whichthe lead wire holding portion 61 is provided in the intermediate member60, these problems can be solved.

<2. Details of Bus Bar Unit>

FIG. 8 is a perspective view of the bus bar unit 40 included in themotor 1 according to an embodiment of the present invention.Specifically, FIG. 8 is a perspective view as seen from the lower side.The bus bar 41 is made of a metal. The bus bar holder 42 is made of aresin. The bus bar unit 40 is formed by insert molding the plurality ofbus bars 41 and the bus bar holder 42. In the present embodiment, thenumber of the bus bars 41 is three. However, the number of the bus bars41 may be plural, and the number of the bus bars 41 may be a numberother than three.

As shown in FIG. 2 and FIG. 8, the bus bar holder 42 has a holder bodyportion 421 and a connector portion 422. The holder body portion 421 hasa cup shape that opens downward. The outer circumference of the holderbody portion 421 is circular. A tubular portion 421 a is provided in thecenter portion of the holder body portion 421. The tubular portion 421 aholds the upper bearing 30 a.

The connector portion 422 extends from a part in the circumferentialdirection of the holder body portion 421 to a radial outside. Theconnector portion 422 has a connector opening 422 a at the end portionof the radial outside. One end portion of each of the bus bars 41 isexposed inside of the holder body portion 421, and the other end portionis exposed to the outside via the connector opening 422 a.

The bus bar 41 has a terminal portion 410 to be connected to the leadwire 222 drawn out from the coil 22. Specifically, the terminal portion410 is provided at one end portion of the bus bar 41 and is exposed tothe inner space of the holder body portion 421. In the presentembodiment, the terminal portion 410 is formed by machining one endportion of the bus bar 41. In the present embodiment, the number of theterminal portions 410 is three. The three terminal portions 410 arearranged in the circumferential direction. In the case where the bus barholder 42 is attached to the housing 50, each of the terminal portions410 is disposed in a position facing the lead wire holding portion 61 inthe axial direction.

FIG. 9 is a plan view of the terminal portion 410 provided at one endportion of the bus bar 41. FIG. 9 is a view of the terminal portion 410seen from the radial inside toward the radial outside. As shown in FIG.9, the terminal portion 410 has a slit 4101 extending axially downwardand fitted with the lead wire 222. A width W of the slit 4101 isnarrower than the diameter of the lead wire 222. In detail, the slit4101 linearly extends from an intermediate position to the lower end ofthe vertical direction of the terminal portion 410. In the presentembodiment, each of the terminal portions 410 has the two slits 4101disposed at intervals in the circumferential direction. That is, each ofthe terminal portions 410 is connected to the two lead wires 222.Between the two slits 4101 aligned in the circumferential direction, adividing groove 4102 dividing the terminal portion 410 into two regionsis provided. In the case where the bus bar holder 42 is attached to thehousing 50, the circumferential position of each of the slits 4101coincides with the circumferential position of each of the lead wires222. Due to this, it is possible to fit each of the lead wires 222 intoeach of the slits 4101.

According to the present embodiment, by fitting the lead wire 222 drawnout from the coil 22 into the slit 4101, it is possible to easily andelectrically connect the lead wire 222 and the bus bar 41. Therefore, itis possible to omit the work of welding the lead wire 222 and the busbar 41. It should be noted that the lead wire 222 and the bus bar 41 maybe welded together. However, since the width W of the slit 4101 isnarrower than the diameter of the lead wire 222, it is possible to fixthe lead wire 222 onto the terminal portion 410 by fitting the lead wire222 into the slit 4101. Therefore, welding may be skipped.

Further, the lead wire 222 fitted into the slit 4101 may be fitted intothe slit 4101 in a state where the insulating coating has been removed.In this case, it is configured so that the width W of the slit 4101 issmaller than the diameter of the lead wire 222 from which the insulatingcoating has been removed. However, the lead wire 222 fitted into theslit 4101 may be fitted into the slit 4101 without the insulatingcoating removed. Even in this case, by scraping off the insulatingcoating when the lead wire 222 is fitted into the slit 4101, anelectrical connection between the terminal portion 410 and the lead wire222 is obtained.

According to the present embodiment, since the bus bar unit 40 has theplurality of terminal portions 410, by disposing the bus bar holder 42in a predetermined location, it is possible to electrically connect theplurality of bus bars 41 and the plurality of lead wires 222 at the sametime. In other words, according to the present embodiment, it ispossible to improve the manufacturing efficiency of the motor 1 becauseit is possible to carry out the process of connecting the plurality ofbus bars 41 to the lead wire 222 at the same time, not carrying out theprocess of connecting the plurality of bus bars 41 to the lead wire 222one by one in sequence.

In the present embodiment, the lead wire 222 extending in the radialdirection is fitted into the slit 4101. The lead wire 222 extending inthe radial direction includes the lead wire 222 extending in a directionincluding the radial direction component. A part of the lead wire 222 isdisposed and held in a direction extending in the radial direction bythe lead wire holding portion 61. Note that the number of the lead wireholding portions 61 is the same as the number of the bus bars 41. In thepresent embodiment, as shown in FIG. 3, the number of the lead wireholding portions 61 is three. The three lead wire holding portions 61are arranged in the circumferential direction. One of the lead wireholding portions 61 holds the two lead wires 222.

The slit 4101 has the width W of the circumferential direction that isnarrower than the diameter of the lead wire 222. In the slit 4101, theportion, held by the lead wire holding portion 61, of the lead wire 222is fitted. As described above, the plurality of terminal portions 410are arranged in the circumferential direction. That is, the plurality ofslits 4101 are arranged in the circumferential direction. In addition,the portions, held by the lead wire holding portion 61, of the pluralityof lead wires 222 are aligned in the circumferential direction. Thecircumferential position of each of the slits 4101 and thecircumferential position of each of the lead wires 222 fitted in each ofthe slits 4101 coincide. Due to this, it is possible to simultaneouslyfit each of the lead wires 222 into each of the slits 4101 by loweringthe bus bar holder 42 disposed above the stator 20 toward the stator 10.That is, it is possible to improve the manufacturing efficiency of themotor 1 because it is possible to simultaneously carry out theelectrical connection between the plurality of bus bars 41 and theplurality of lead wires 222.

As shown in FIG. 8, the bus bar holder 42 has a protrusion 423protruding radially outward. Specifically, the protrusion 423 isprovided on the outer circumferential surface of the holder body portion421. In the present embodiment, the number of the protrusions 423 isthree. However, the number of the protrusions 423 may be changed. Thehousing 50 has a recess portion recessed radially outward or a radiallypenetrating hole portion or notch portion. At least a part of theprotrusion 423 is fitted into the recess portion, the hole portion, orthe notch portion. According to this, it is possible to carry out acircumferential positioning of the bus bar unit 40 with respect to thestator 20 by the protrusion 423 and the recess portion, the hole portionor the notch portion. Due to this, it is possible to easily connect theterminal portion 410 and the lead wire 222.

In the present embodiment, for example, as shown in FIG. 1 and FIG. 3,the housing 50 has a notch portion 53. The flange 52 has an extendingportion 54 axially extending in the outer circumference. The extendingportion 54 is a member identical to the flange 52. In particular, theflange 52 has the pair of extending portions 54 disposed at intervals inthe circumferential direction. The notch portion 53 is a gap between thepair of extending portions 54. In the present embodiment, the number ofthe pairs of extending portions 54 is the same as the number of theprotrusions 423, which is three. The plurality of the pairs of extendingportions 54 are arranged in the circumferential direction. In the casewhere the notch portion 53 is constituted by the pair of extendingportions 54, since the position of the notch portion 53 becomes easy tosee, it is possible to efficiently carry out the work of fitting atleast a part of the protrusion 423 into the notch portion 53.

In the present embodiment, a part of the protrusion 423 is fitted intothe notch portion 53. As shown in FIG. 8, the protrusion 423 has aprotruding portion 423 a protruding radially outward on an end face ofthe radial outside. The protruding portion 423 a is fitted into thenotch portion 53. Further, in the case where the housing 50 has a recessportion or a through hole instead of the notch portion 53, the recessportion or the through hole may be provided on the side wall of thehousing 50, for example.

The flange 52 has a claw portion 55 that protrudes radially inward fromthe extending portion 54 and contacts the upper surface of theprotrusion 423. The claw portion 55 protrudes radially inward from theupper end of the extending portion 54 in detail. The claw portion 55 isa member identical to the extending portion 54. The claw portion 55 isobtained, for example, by bending the upper portion of the extendingportion 54 extending axially upward at a substantially right angle afterthe protruding portion 423 a is fitted into the notch portion 53. By thecontact between the claw portion 55 and the protrusion 423, it ispossible to prevent the bus bar holder 42 from being lifted upward andto carry out an axial positioning of the bus bar unit 40 with respect tothe stator 20.

In the present embodiment, the bus bar holder 42 is in contact with theupper surface of the stator core 21. In detail, the holder body portion421 has a holder rib 4211 that protrudes radially inward from the innercircumferential surface on the inner circumference. The lower surface ofthe holder rib 4211 comes into contact with the upper surface of thecore back 212. According to the present configuration, it is possible tocarry out an axial positioning of the bus bar unit 40 by the stator core21. It is possible to easily manage the dimensional tolerance becausethe axial positioning of the bus bar unit 40 with respect to the stator20 is carried out by using a part of the stator 20.

However, the axial positioning of the bus bar holder 42 with respect tothe stator 20 may be carried out using another portion. The axialpositioning may be carried out with, for example, a configuration inwhich the lower surface of the protrusion 423 is in contact with theupper surface of the flange 52. According to the present configuration,it is possible to reduce the work load for positioning because it ispossible to carry out the circumferential and axial positioning of thebus bar unit 40 with respect to the stator 20 using the same protrusion423.

<3. Details of Intermediate Member>

As shown in FIG. 3, the intermediate member 60 has an annular portion 62and a rib 63. The intermediate member 60 is made of, for example, aresin. The annular portion 62 is provided with the lead wire holdingportion 61 on its upper surface. In the present embodiment, the numberof the lead wire holding portions 61 is plural, more specifically,three. The annular portion 62 is circular. The plurality of lead wireholding portions 61 are arranged in the circumferential direction.

FIG. 10 is a vertical sectional view of a part of the intermediatemember 60 included in the motor 1 according to an embodiment of thepresent invention. As shown in FIG. 3 and FIG. 10, the rib 63 protrudesradially inward from the inner circumferential surface of the annularportion 62. Further, the rib 63 protrudes downward from the axial lowerend of the annular portion 62. The annular portion 62 and the rib 63 area single member. The plurality of ribs 63 are provided. The plurality ofribs 63 are arranged at intervals in the circumferential direction.

FIG. 11 is a view for explaining the relationship between theintermediate member 60 and the stator 20. As shown in FIG. 11, the coreback 212 has a groove portion 2121 recessed radially outward on theinner circumferential surface and extending in the axial direction. Morespecifically, the plurality of grooves 2121 are provided. The pluralityof grooves 2121 are arranged at intervals in the circumferentialdirection. In a state where the intermediate member 60 is disposed onthe upper surface of the core back 212, the rib 63 is fitted into thegroove portion 2121. More specifically, each of the plurality of ribs 63is fitted into the separate groove 2121.

According to the present configuration, it is possible to carry out thecircumferential and radial positioning of the intermediate member 60 bythe groove portion 2121 provided in the core back 212. Due to this, thelead wire 222 held by the lead wire holding portion 61 provided in theintermediate member 60 can be accurately fitted into the slit 4101 ofthe terminal portion 410.

FIG. 12 is an enlarged view of the lead wire holding portion 61 and itssurroundings. FIG. 13 is a further enlarged perspective view of the leadwire holding portion 61 and its surroundings. In FIG. 13, only theconfiguration included in the intermediate member 60 is shown.

As shown in FIG. 12 and FIG. 13, the lead wire holding portion 61 has abox shape. Specifically, the lead wire holding portion 61 has arectangular shape in plan view from the axial direction. The lead wireholding portion 61 has a wall portion 611. The wall portion 611 bisectsthe inner space of the lead wire holding portion 61 in thecircumferential direction. The wall portion 611 separates the pluralityof lead wires 222 from each other. In the present embodiment, the wallportion 611 separates the two lead wires 222.

The lead wire holding portion 61 has two regions R1 and R2 separated bythe wall portion 611. Each of the regions R1 and R2 has a notch groove612 provided by cutting out a wall surface orthogonal to the radialdirection into a U shape. Each of the regions R1 and R2 has the twonotch grooves 612 disposed at intervals in the radial direction. Each ofthe lead wires 222 is held in the lead wire holding portion 61 in astate of being fitted into the two notch grooves 612 aligned in theradial direction. The lead wire holding portion 61 holds the pluralityof lead wires 222. Specifically, each of the lead wire holding portions61 holds the two lead wires 222 extending in the radial direction. Asshown in FIG. 12, in a state where the lead wire 222 is fitted into theslit 4101, most of the terminal portion 410 is inserted into the leadwire holding portion 61.

As shown in FIG. 13, it is preferable that the intermediate member 60has a first overhanging portion 64 protruding radially inward at aposition in the circumferential direction where the lead wire holdingportion 61 is provided. It is preferable that the first overhangingportion 64 is located lower than the lead wire holding portion 61. Thefirst overhanging portion 64 may, for instance, protrude to the upperend of the insulator 23 positioned radially inward and contact theinsulator 23.

According to the present configuration, it is possible to improve therigidity of the intermediate member 60 by increasing the radialthickness of the intermediate member 60 at the position where the leadwire holding portion 61 is provided. Due to this, when the terminalportion 410 is inserted into the lead wire holding portion 61 and thelead wire 222 is fitted into the slit 4101, it is possible to suppressdeformation of the intermediate member 60. In the configuration shown inFIG. 12, the first overhanging portion 64 is omitted, and such aconfiguration may be adopted.

As shown in FIG. 13, it is preferable that the intermediate member 60has a second overhanging portion 65 that protrudes radially inward fromthe lead wire holding portion 61. It is preferable that the secondoverhanging portion 65 is formed on a surface facing radially inward ofthe lead wire holding portion 61. The second overhanging portion 65 islocated above the first overhanging portion 64. In the presentembodiment, the second overhanging portion 65 is a rectangularparallelepiped shape that has a rounded corner at the radial inside andextends from the lower end to the upper end of the lead wire holdingportion 61.

By providing the second overhanging portion 65, it is possible to guidethe plurality of lead wires 222 held by the lead wire holding portion 61to an appropriate holding position while avoiding contact with eachother. It is preferable that the second overhanging portion 65 islocated radially inside the wall portion 611. According to the presentconfiguration, it is possible to provide the second overhanging portion65 at a portion where the rigidity of the lead wire holding portion 61is high. Further, since the wall portion 611 is provided at a positionwhere the two regions R1 and R2 are bisected, it is possible to guidethe lead wire 222 to the holding position with good balance by disposingthe second overhanging portion 65 on the radial inside of the wallportion 611.

In the configuration shown in FIG. 12, the second overhanging portion 65is not provided in the lead wire holding portion 61 provided at thecenter among the three lead wire holding portions 61 aligned in thecircumferential direction. This is out of consideration that it is lesslikely for the lead wires 222 to come into contact with each other whenthe two lead wires 222 are guided to the lead wire holding portion 61.However, the second overhanging portion 65 may also be provided in thelead wire holding portion 61.

<4. Points to be Noted>

The configuration of the above-described embodiment is merely an exampleof the present invention. The configuration of the embodiment may beappropriately changed without exceeding the technical idea of thepresent invention. Further, it is also possible to implement a pluralityof modified examples appropriately described above by appropriatelycombining them within a possible range.

Exemplary embodiments of the present invention can be widely applied to,for example, motors used for home appliances, automobiles, ships,aircrafts, trains, and the like. Exemplary embodiments of the presentinvention can be applied to, for example, a motor for an electric oilpump.

While preferred embodiments of the present invention have been describedabove, it is to be understood that variations and modifications will beapparent to those skilled in the art without departing from the scopeand spirit of the present invention. The scope of the present invention,therefore, is to be determined solely by the following claims.

The invention claimed is:
 1. A motor comprising: a rotor including ashaft centered on a vertically extending center axis; a stator disposedradially opposite to the rotor and including a plurality of coils; abearing supporting the shaft; a bus bar unit disposed on an upper sidein an axial direction of the stator; and a housing surrounding andfixing the stator; wherein the bus bar unit includes: a plurality of busbars including a terminal portion connected to a lead wire drawn outfrom the coil; and a bus bar holder holding the plurality of bus bars;the terminal portion includes a slit which extends axially downward andinto which the lead wire is fitted; a width of the slit is narrower thana diameter of the lead wire; the bus bar holder includes a protrusionprotruding radially outside; the housing includes a recess portionrecessed radially outward or a radially penetrating hole portion ornotch portion; and at least a portion of the protrusion is fitted intothe recess portion, the hole portion, or the notch portion.
 2. The motoraccording to claim 1, wherein the lead wire extending in a radialdirection is fitted into the slit; and a circumferential width of theslit is narrower than the diameter of the lead wire.
 3. The motoraccording to claim 1, wherein the housing includes a flange extendingradially outward; and a lower surface of the protrusion is in contactwith an upper surface of the flange.
 4. The motor according to claim 1,wherein the stator includes an annular stator core; and the bus barholder is in contact with an upper surface of the stator core.
 5. Themotor according to claim 4, wherein the housing includes a flangeextending radially outward; and the flange includes: an extendingportion extending in an axial direction on an outer circumference; and aclaw portion protruding radially inward from the extending portion andbeing in contact with an upper surface of the protrusion.
 6. The motoraccording to claim 5, wherein the flange includes a pair of theextending portions disposed at intervals in a circumferential direction;the housing includes the notch portion; and the notch portion is a gapbetween the pair of extending portions.
 7. The motor according to claim1, wherein the stator includes an insulator disposed between the coiland a tooth around which a conductive wire defining the coil is wound;and the insulator includes a lead wire holding portion that holds thelead wire.
 8. The motor according to claim 1, further comprising anintermediate member positioned between the stator and the bus barholder, wherein the intermediate member includes a lead wire holdingportion that holds the lead wire.
 9. The motor according to claim 8,wherein the stator includes: a plurality of teeth around which aconductive wire defining the coil is wound, and which are arranged in acircumferential direction; and an annular core back located radiallyoutside of the plurality of teeth;  the core back includes a grooveportion recessed radially outward and axially extending on acircumferential surface;  the intermediate member includes: an annularportion provided with the lead wire holding portion on an upper surfacethereof; and a rib protruding radially inward from a circumferentialsurface of the annular portion and protruding downward from an axiallylower end of the annular portion; and the rib is fitted into the grooveportion.
 10. The motor according to claim 8, wherein the intermediatemember includes a first overhanging portion protruding radially inwardin a circumferential position where the lead wire holding portion isprovided.
 11. The motor according to claim 8, wherein the lead wireholding portion holds a plurality of the lead wires; and theintermediate member includes a second overhanging portion protrudingradially inward from the lead wire holding portion.
 12. The motoraccording to claim 11, wherein the lead wire holding portion includes awall portion separating the plurality of lead wires from each other; andthe second overhanging portion is located radially inside of the wallportion.